Size- and Shape-Controlled Conversion of Tungstate-Based Inorganic-Organic Hybrid Belts to WO3 Nanoplates with High Specific Surface Areas

Two-dimensional monoclinic WO3 nanoplates with high specific surface areas are synthesized through a novel conversion process using tungstate-based inorganic-organic hybrid micro/nanobelts as precursors. The process developed involves a topochemical transformation of tungstate-based inorganic-organic hybrid belts into WO,3 nanoplates via an intermediate product of H2WO4 nanoplates, utilizing the similarity of the W-O octahedral layers in both H2WO4 and WO3. The as-obtained WO3 nanoplates show a single-crystalline nanostructure with the smallest side along the [001] direction. The WO3 nanoplates are 200-500 nm x 200-500 nm x 10-30 nm in size, and their specific surface areas are up to 180 m(2) g(-1). Photocatalytic measurements of visible-light-driven oxidation of water for O-2 generation in the presence of Ag+ ions indicate that the activity of the as-obtained WO3 nanoplates is one order of magnitude higher than that Of commercially available WO3 powders.